Most sprayed insulation materials are based upon petrochemical products and therefore are restricted in their use by the possibility of degrading by flame or heat with a subsequent toxic and/or fire spread hazard.
The usual methods to overcome these fire hazard risks in insulation is to use a dry board insulation material such as vermiculite or gypsum. These have the disadvantage of both being subject to water absorption and a tendency to expand, increase drag weight and pull away in humid or extreme weather conditions. Plus, such a dry panel has to be cut to shape to encase angles, etc. Also, dry insulation panels are restricted by the very nature of their base structures to interior use.
My present invention overcomes the foregoing disadvantages by allowing on-site use of cold state, pre-expand perlite particles (loose form) to be premixed in a cold state, passed to a spray gun nozzle, without fracture or breakdown of the natural geodetic strength or known insulation qualities of expanded perlite particles whereby a coating of any predetermined thickness up to an immediate 2 inches can be applied to any substrate capable to receive it, following any angles or contours of said substrate with a uniformity of desired thickness of coating. This coating will provide the predetermined insulation requirements plus having the abilities to act as a fire barrier that will not degrade or emit toxics at temperatures in excess of 1700.degree. F. for periods of time that are predetermined by the initial insulation thickness.
The insulation as described herein would have no need of exothermics to cure apart from an ambient temperature in excess of 40.degree. F.
Also, by the nature of the aggregate, i.e. expanded perlite particles, the material would be abundant and the cost would be inexpensive.
This invention relates to a cold mixable, sprayable and cold curable, noncombustible, nontoxic material that is useful as an insulation and as a fire, acoustic and weather barrier onto any substrate that is capable to receive said material, plus pressure feeding pre-expanded perlite particles without destroying the geodetic structure and strength of said particles and known insulation qualities of cold state perlite. The material can also be used to fill confined spaces such as wall cavities, attics and hollow partitions in the construction industries. Also, it can be used as fire, acoustic and insulation barriers when used for vehicles, ships, transporters and any other form of container that has need of thermal insulation at high and low temperatures.
Sprayed or foamed-in-place insulation materials presently in use generally are derived from petrochemical products, either as a source of the basic material mass or as a source of bonding or adhesive agents thereafter. These materials are not only becoming increasingly expensive and difficult to obtain, but also can, by virtue of their combustibility, become fire hazards and also give rise to toxic and lethal fumes and smoke when used in buildings or other confined areas. Petrochemical products used as external insulation can degrade from exposure to extreme weather conditions and solar radiation. Accordingly, lamination or coating to provide a barrier against weathering may be required.
Johnson et al, in U.S. Pat. No. 3,360,046 disclose a cement composition, containing silica flour and vermiculite or perlite, which can be pumped into wells to insulate boreholes used for secondary and tertiary recovery of oil. This material is cured by heating at about 100.degree. F. at 100% relative humidity for 24 hours. It is apparent that this curing cycle would be unacceptable for use in confined spaces in the building trades.
Bollaert et al (U.S. Pat. No. 2,585,366) describe a lightweight concrete mixture containing Portland cement, cellular perlite and filler-grade finely comminuted silica, such as distomaceous earth. Bollaert et al view silica of very small particle size, of the order of 70% finer than 10 microns, as critical in decreasing the tendency of Portland cement and perlite to separate and in producing a product having strength close to that of concrete based on heavy aggregate.
Shea, Jr. et al (U.S. Pat. No. 2,698,251) teach manufacture of lightweight siliceous insulation material in which a particulate siliceous filler is pretreated to produce a reactive silica coating on the particles, which are combined with an alkaline earth metal binder and generally heated above 80.degree.-100.degree. C. to obtain a cured product.
Sucetti, in U.S. Pat. No. 2,993,016, discloses a dry plaster mix containing aggregate, clay, water-soluble cellulose derivative and aminoplast resin. The mix can be combined with water to yield a material which is sprayable and which hardens in a few hours, apparently because of reaction between the cellulose derivative and aminoplast.